Security features are used to reduce or prevent counterfeiting of items. These items may have a high intrinsic value, such as banknotes, or they may be critical parts in other items, such as brake pads in airplanes. By tagging an item with a security feature, the authenticity of the item can subsequently be confirmed by validating that the security feature is genuine.
One disadvantage of conventional security features is that counterfeiters can spend a large amount of time and money to replicate a particular security feature, and, when perfected, can then use the replicated security feature on an unlimited number of counterfeited items. When this occurs, the owner of the items may either change the security feature or add more security features, but neither of these actions can safeguard items that have already been issued with the now compromised security feature. This is a fundamental problem with even the most advanced security feature.
Unique security features could be created, for example, using variable data printing (VDP). However, VDP typically requires a digital printing press. For some applications, a huge number of different security features are required, for example, if a unique security feature was needed for each bottle of a certain brand of pain killer, or for each twenty dollar banknote. This is problematic for VDP because it is not currently economically-viable to produce a large number of security features in high volumes (for example, a million security features) and at high speeds (for example, one thousand security features per minute).